WO1993020707A1

WO1993020707A1 - Anti-cavity chewing gum and method of fighting tooth decay using glyceraldehyde

Info

Publication number: WO1993020707A1
Application number: PCT/US1993/002883
Authority: WO
Inventors: Michael J. Greenberg
Original assignee: WM Wrigley Jr Co
Current assignee: WM Wrigley Jr Co
Priority date: 1992-04-09
Filing date: 1993-03-25
Publication date: 1993-10-28
Anticipated expiration: 1994-10-09
Also published as: AU3938293A

Abstract

A chewing gum formulation to fight cavities comprises sufficient glyceraldehyde to give the chewing gum anti-caries properties. Also disclosed is a method of reducing or preventing dental caries by inhibiting the growth of Streptococcus mutans in the presence of fermentable carbohydrates in the mouth. This method comprises contacting the teeth with chewing gum containing glyceraldehyde, wherein the glyceraldehyde is present in sufficient quantity to give the chewing gum anti-caries properties.

Description

ANTI-CAVITY CHEWING GUM AND METHOD OF FIGHTING TOOTH DECAY USING GLYCERALDEHYDE

BACKGROUND OF THE INVENTION This invention relates to a method for preventing or reducing dental caries wherein the carbohydrate glyceraldehyde is employed in chewing gum to inhibit growth of Streptococcus mutans ("S. mutans") in the mouth. The present invention also relates to chewing gum formulations containing glyceraldehyde. Foods containing natural sugars such as sucrose and dextrose have long been recognized as a major contributing cause of dental caries. The sugars are easily utilizable sources of nutrition for bacteria, specifically S. mutans found in the mouth. This bacteria is also responsible for the formation of plaque. S. mutans ferments residual sugar, thereby producing acids that dissolve the minerals of the teeth.

In recent years, certain anti-cariogenic substances have been incorporated into chewing gum and other orally-usable products. For example, U.S. Patent No. 4,390,523, issued June 28, 1983, to Huchette et al. , teaches the substitution of sorbose for sucrose as a sweetener in chewing gum in order to reduce the production of fermentation acids in the mouth.

U.S. Patent Nos. 4,457,921, issued July 3, 1984, and 4,508,713 issued April 2, 1985, both to Stroz et al. , teach a method for treating teeth with hydrogenated starch hydrolysate, in conjunction with sucrose, in a chewing gum composition, in order to reduce dental caries. U.S. Patent No. 4,374,122, issued February 15, 1983, also to Stroz et al., teaches the use of a compound comprising 3,4-dihydro-6-methyl-l,2,3- oxathiazine-4-one-2,2-dioxide, or the sodium, ammonium, potassium or calcium salts thereof, in an orally-usable carrier, including chewing gum, in order to reduce dental caries.

U.S. Patent No. 4,518,581, issued May 21, 1985, to Miyake et al., teaches the use of a substance selected from the group consisting of isomaltosyl mono-, di- and tri-glucoses, and reduction products thereof, in orally-usable products including chewing gum in order to reduce dental caries.

U.S. Patent No. 4,714,612, issued December 22, 1987, to Nakamura et al. , teaches the use of γ-globulin in chewing gum to combat Bacteroides qinσivalis from colonizing in the mouth.

European Patent Application 0 342 369 A2, filed by Lembke et al. and published November 23, 1989, in the name of Biodyn AG, teaches the use of galactose in numerous orally-usable products, including chewing gum, in order to protect against dental caries.

U.S. Patent No. 3,629,395, issued December 21, 1971, to Litchfield et al._r teaches the use of 1- hydroxyethylphosphonic acid; 1,2-dihydroxyethyl- phosphonic acid; 1-aminoethylphosphonic acid; 2-amino- ethylphosphonic acid; 1-aminomethylphosphonic acid; 2- amino-4-phosphonobutyric acid; 2-amino-3-phosphono- propionic acid; glyceraldehyde-3-phosphoric acid; and glyceraldehyde diphosphate, in a gum formulation, to prevent dental caries. In an effort to reduce dental caries, artificial sweeteners and non-fermentable carbohydrates such as polyols have been used in place of the sugars which are used to give bulk to chewing gum. However, all polyols have the disadvantage of causing gastrointestinal disturbances if consumed in too great a quantity. It would be advantageous to be able to use a carbohydrate or carbohydrate-like compound as a bulking agent in chewing gum that would not contribute to dental caries or cause gastrointestinal disturbances.

SUMMARY OF THE INVENTION It has been surprisingly found that the carbohydrate glyceraldehyde inhibits bacterial growth and may thus be used in chewing gum and confections to reduce the incidence of dental caries. Amounts of glyceraldehyde in a chewing gum formula sufficient to inhibit S. mutans may reduce the development of dental caries.

In accordance with one aspect of the present invention, there is provided a chewing gum formulation containing an amount of glyceraldehyde effective to give the chewing gum anti-caries properties, preferably at least 0.5% by weight glyceraldehyde, and more preferably from about 0.5 to about 40% by weight glyceraldehyde. Even more preferably, the weight range of glyceraldehyde is from about 1 to about 35%, and still more preferably, from about 5 to about 30%. The present invention also provides a method of treating teeth to reduce or prevent dental caries by gradually administering glyceraldehyde over a period of time. This is accomplished by using a chewing gum formulation containing an amount of glyceraldehyde effective to give the gum anti-caries properties.

The method described above preferably utilizes a chewing gum formulation containing at least 0.5% by weight glyceraldehyde, more preferably from about 0.5 to about 40% by weight glyceraldehyde. Even more preferably, the method utilizes a chewing gum formulation wherein the weight range of glyceraldehyde is from about 1 to about 35%, and still more preferably, from about 5 to about 30%.

DETAILED DESCRIPTION Glyceraldehyde is a 3-carbon carbohydrate

(aldotriose) , and is the simplest aldose. Its melting point is reported at temperatures from 138°C to 145°C. It is soluble in water, alcohol and ether, but insoluble in benzene. Glyceraldehyde has an empirical formula of C₃H₆0₃ and its molecular weight is 90.08. The structure of glyceraldehyde is shown below:

CHO

H C — OH

CH₂0H

At present _r glyceraldehyde is commonly used as an ingredient in cosmetics and medicants, for biochemical research, for the preparation of polyesters and adhesives, as a cellulose modifier, and in leather tanning. It is a chemical and metabolic intermediate, produced in the body by the oxidation of sugars, and although it is considered to be nontoxic and tasteless, it is not yet an approved food ingredient. It exists in D and L optical isomers, both of which (and their mixtures) are useful in the present invention. The DL mixture is preferred, since it is readily available commercially.

In vitro tests which are part of the present invention, and which are described in more detail below, indicate that glyceraldehyde inhibits growth of S. mutans. An initial test revealed the surprising effectiveness of a 5% solution of glyceraldehyde over negative controls of xylose solutions. Later tests showed that glyceraldehyde was effective in a 2% solution and even to a slight degree, in a 0.5% solution. Apparently at 0.1%, this level had a short term effect. These tests show glyceraldehyde was effective in inhibiting the growth of S. mutans. and is thus bacteriostatic. In some instances the population of S. mutans decreased, indicating that bacteria may be killed by glyceraldehyde. This killing action is described as bactericidal. Chewing gum is used to administer glyceraldehyde into the mouth. In general, a chewing gum composition comprises a water soluble bulk portion; a water insoluble, chewable, chewing gum base portion; and, typically, water insoluble flavor ingredients. The water soluble bulk portion, which in the case of the invention includes glyceraldehyde, dissolves with a portion of the flavor over a period of time, while the consumer chews the gum. The gum base portion is retained in the mouth throughout the chew. The insoluble gum base generally includes elastomers, resins, fats, oils, waxes, softeners and inorganic fillers. The elastomers may include polyisobutylene, isobutylene-isoprene copolymer, styrene butadiene rubber and natural latexes such as chicle. The resins may include polyvinyl acetate, ester gums and terpene resins. Low molecular weight polyvinyl acetate is a preferred resin. Fats and oils may include animal fats such as lard and tallow, vegetable oils such as soybean and cottonseed oils, hydrogenated and partially hydrogenated vegetable oils, and cocoa butter. Commonly used waxes include petroleum waxes such as paraffin and macrocrystalline wax, natural waxes such as beeswax, candelilla, carnauba and polyethylene wax. The present invention contemplates the use of any commercially acceptable chewing gum base. The gum base typically also includes a filler component such as calcium carbonate, magnesium carbonate, talc, dicalcium phosphate and the like, in an amount from about 5 to about 60% by weight of the gum base; softeners, including glycerol monostearate and glycerol triacetate; and optional ingredients such as antioxidants, colors and emulsifiers. The gum base constitutes from about 5 to about 95% by weight of the chewing gum, more typically from about 10 to about 50% by weight of the chewing gum, and most commonly from about 20 to about 35% by weight of the chewing gum.

The water soluble portion of the chewing gum may include softeners, bulk sweeteners, high intensity sweeteners, flavoring agents and combinations thereof. Softeners such as glycerin are added to the chewing gum in order to optimize the chewability and mouth feel of the gum. The softeners, which are also known as plasticizers or plasticizing agents, constitute from about 0.1 to about 15% by weight of the chewing gum. Aqueous sweetener solutions such as those containing sorbitol, hydrogenated starch hydrolysates, syrups of xylitol, maltitol, hydrogenated isomaltulose and other polyols, corn syrup and combinations thereof, may also be used as softeners and binding agents in the chewing gum.

Bulk sweeteners constitute from about 5 to about 90% by weight of the chewing gum, more typically from about 20 to about 80% by weight of the chewing gum and most commonly from about 30 to about 60% by weight of the chewing gum.

Sweeteners contemplated by the present invention for use in chewing gum include both sugar and sugarless components. Sugar sweeteners generally include saccharide-containing components commonly known in the chewing gum art. These sugar sweeteners include but are not limited to sucrose, dextrose, maltose, dextrin, dried invert sugar, fructose, levulose, galactose, corn syrup solids and the like, alone or in any combination.

Any combination of sugar and/or sugarless sweeteners may be employed in the chewing gum.

Further, a sweetener may be present in a chewing gum in whole or in part as a water soluble bulking agent. It is a portion of the usual sweetener/bulking agent which is replaced with glyceraldehyde, in the quantities described above. In addition, the softener may be combined with a sweetener such as an aqueous sweetener solution.

Bulk sweeteners preferably include sugarless sweeteners and components. Sugarless sweeteners include components with sweetening characteristics but are devoid of the commonly known sugars. Sugarless sweeteners include but are not limited to sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol, hydrogenated isomaltulose, and the like, alone or in combination.

High intensity sweeteners may also be present and are commonly used with sugarless sweeteners. When used, high intensity sweeteners typically constitute from about 0.001 to about 5% by weight of the chewing gum, preferably from about 0.01 to about 1% by weight of the chewing gum. Typically, high intensity sweeteners are at least 20 times sweeter than sucrose. These may include but are not limited to sucralose, aspartame, salts of acesulfame, alitame, saccharin and its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin, monellin, and the like, alone or in combination.

The flavoring agent should generally be present in the chewing gum in an amount within the range of from about 0.1 to about 15% by weight of the chewing gum, preferably from about 0.2 to about 5% by weight of the chewing gum, most preferably from about 0.5 to about 3% by weight of the chewing gum. Flavoring agents may include essential oils, synthetic flavors or mixtures thereof including but not limited to oils derived from plants and fruits such as citrus oils, fruit essences, peppermint oil, spearmint oil_r other mint oils_r clove oil, oil of wintergreen, anise and the like. Artificial flavoring agents and components may also be used in the chewing gum.

Natural and artificial flavoring agents may be combined in any sensorially acceptable fashion.

Optional ingredients such as colors, emulsifiers pharmaceutical agents and additional flavoring agents may also be included in chewing gum.

In general, chewing gum is manufactured by sequentially adding the various chewing gum ingredients to any commercially available mixer known in the art. After the ingredients have been thoroughly mixed, the gum mass is discharged from the mixer and shaped into the desired forms such as by rolling into sheets and cutting into sticks, extruding into chunks, or casting into pellets. Generally, the ingredients are mixed by first melting the gum base and adding it to the running mixer. The base may also be melted in the mixer itself. Color may also be added at this time. A softener such as glycerin may then be added next along with syrup and a portion of bulking agent, which may include glyceraldehyde. Further portions of the bulking agents, including any remaining glyceraldehyde, may then be added to the mixer.

The present invention contemplates the blending of glyceraldehyde into the chewing gum, thus allowing its gradual release into the mouth as the gum is chewed. Glyceraldehyde may be mixed with the chewing gum ingredients at any time during the manufacturing process, but preferably it is mixed in with the bulking agent. Although in a lesser quantity, glyceraldehyde may also be coated on the outside of the gum. The following examples are not to be construed as limitations upon the present invention, but are included merely as an illustration of various embodiments.

EXAMPLES

Example 1: Testing 5% Glyceraldehyde

This example demonstrates that glyceraldehyde effectively inhibits or kills S. mutans.

Five gram samples of D-erythrose (85% solution in water from Aldrich Chemical Co., Milwaukee, Wisconsin), D,L-glyceraldehyde (Aldrich, 98% purity), xylose (Aldrich) and xylose (Roquette) were obtained. Five percent test solutions of each were prepared from 10% stock solutions (1 gram of sample per 10 grams of solution) by diluting 1:1 (1 gram of 10% solution per 1 gram of diluent) with sterile distilled water for the Paper Disc assay and Trypticase Soy Broth ("TSB") for the broth assay.

An S. mutans culture (ATCC 25175) was prepared with TSB and incubated 24 hours at 35^βC.

Paper Disc Inhibition tests were performed, wherein spread plates were prepared by inoculating each Typtone Glucose Yeast Extract agar plate (TGY) with 0.1 ml of a 1:1000 dilution of the 24-hour S. mutans culture. The plate was then allowed to dry for 30 minutes. For each test solution, two 12.5 mm sterile discs were saturated with 50 microliters of solution and each was placed in the center of an inoculated TGY plate. Two additional discs were saturated with sterile distilled water to serve as negative controls. These plates were incubated for 24 hours at 35°C. After incubation, the plates were observed for clearing zones around the discs, and the diameter of the zone was measured. After 24 hours of incubation, a zone of inhibition around the discs with 5.0% glyceraldehyde was visible. This indicates that the glyceraldehyde effectively inhibited S. mutans (Table 1) .

Table 1: Results of Disc Inhibition Tests of Four Carbohydrates on s. mutans

Sample Plate Zone Diameter (mm)*

Erythrose 1 <12.5

Erythrose 2 <12.5

Glyceraldehyde 1 39

Glyceraldehyde 2 36

Xylose (Aldrich) 1 <12.5 Xylose (Aldrich) 2 <12.5

Xylose (Roquette) 1 <12.5

Xylose (Roquette) 2 <12.5 * Each result is the average of 3 measurements.

Inhibition in TSB was also tested. An overnight culture of S. mutans was diluted 1:1000. Then 0.1 ml of this culture was added to tubes containing 5.0% of glyceraldehyde, erythrose or xylose in TSB. The tubes were incubated in a 35°C water bath. After 0, 4, 8, 24, and 48 hours in the water bath, serial dilutions of the tube solutions were plated. A tube prepared without carbohydrates was also used as a control. The results are expressed in Table 2 as the number of viable colony forming units per milliliter of solution (cfu/ml) , and were consistent with those of the Disc Inhibition Test. Initial plate counts for S_^ mutans ranged from 23,000 cfu/ml to 60,000 cfu/ml (Table 2). After 4 hours of incubation at 35°C, counts decreased to <10 cfu/ml in the glyceraldehyde solution, and remained under 10 cfu/ml through the 48-hour plating. After 8 hours of incubation at 35^βC, counts increased between 5 and 12-fold for the no-carbohydrate control and xylose. After 24 hours of incubation, counts increased between 2,300 and 10,000-fold, and remained relatively constant through the 48 hour plating.

These data indicate that growth rates in the tubes containing xylose did not vary significantly from growth rates in tubes containing straight TSB. These results support the observations of the disc inhibition plates that xylose has no inhibitory effect on S. mutans. In contrast, in tubes containing glyceraldehyde, S. mutans died. The growth rate in the tubes containing glyceraldehyde corresponded to the results obtained on the disc inhibition plates. These results show that glyceraldehyde has a bacteriostatic or bactericidal effect in excess of that of a negative control, such as xylose, i.e., that glyceraldehyde effectively inhibits or kills S. mutans.

Table 2: Results of Inhibition Tests of Four Carbohydrates on S. mutans

Time (hours) Aerobic Plate Count (cfu/ml)

Control 0 60,000

4 69,000

8 120,000

24 1,200,000,000

48 1,100,000,000

Erythrose 0 36,000

4 <10

8 <10

24 <10

48 <10

Glyceraldehyde 0 23,000

4 <10

8 <10

24 <10

48 <10

Xylose (Aldrich)

0 39,000

4 110,000

8 200,000

24 460,000,000

48 570,000,000

Xylose (Roquette)

0 26,000

4 123,000 8 290,000

24 680,000,000

48 400,000,000

Example 2: Testing 0.1%, 0.5%. and 2.0% Glyceraldehyde

This example demonstrates the dose-efficacy relationship between the concentration of inhibitory carbohydrate and bacterial multiplication. Using the same methodology as above, 5 grams of D-erythrose and 10 grams of D,L-glyceraldehyde were dissolved and diluted to obtain four concentrations ranging between 0.10% and 2.0%. This was done by preparing 10% stock solutions and diluting them according to the following schedule:

2.0 grams of 10% solution was diluted with 8.0 grams of diluent to yield 2.0% solution. 1.0 gram of 10% solution was diluted with 9.0 grams of diluent to yield 1.0% solution.

2.0 grams of 2% solution was diluted with 6.0 grams of diluent to yield 0.5% solution. 1.0 gram of 1% solution was diluted with 9.0 grams of diluent to yield 0.1% solution.

Water was the diluent for the disc assay and TSB was the diluent for the broth assay. Two strains of S. mutans (ATCC 25175 and ATCC 27351) were prepared in TSB incubated 24 hours at 35°C before inhibition testing.

Disc Inhibition Test: After 24 hours' incubation there was a zone of inhibition visible on plates containing discs with 2.0% glyceraldehyde (Table 3) . Like Example 1, the results in TSB also showed inhibition. Initial plate counts in the control and glyceraldehyde plates for ATCC 25175 ranged from 3,300 cfu/ml (2.00% glyceraldehyde, Table 4) to 4,400 cfu/ml (control); and for ATCC 27351, from 1,900 cfu/ml (control and 2.00% glyceraldehyde) to 2,400 cfu/ml

(0.50% glyceraldehyde) . After 4 hours of incubation at 35^βC, counts decreased to <10 cfu/ml for both cultures in 2.0% glyceraldehyde and 0.5% glyceraldehyde

Table 3: Results of Disc Inhibition Tests on S. mutans

* Each result is the average of 3 measurements.

solutions, and remained below 10 cfu/ml through the 48 hour plating. The three tubes containing TSB broth with 0.1% glyceraldehyde exhibited inhibition between the 8 and 24 hour platings, but all three showed increased growth by the 48 hour plating.

These data indicate that tubes containing 0.1% glyceraldehyde showed some short term inhibition in broth. The effect was temporarily bacteriostatic as there was little change in the viable count. In tubes containing 0.5% glyceraldehyde and 2.0% glyceraldehyde

S. mutans died. These levels were bactericidal in broth, but only the 2.0% glyceraldehyde was bactericidal by disc assay. Table 4: Results of Broth Inhibition Test for Glyceraldehyde on s. mutans % Glyceraldehyde 0.00 0.10 0.50 2.00

(Control) Time (Hours)

Table 5: Results of Broth Inhibition Test for Erythrose on s. mutans

% Erythrose 0.10 0.50 2.00

Time (Hours)

ATCC 25175

0 3,500

4 6,100

8 5,100 24 210,000,000 48 48,000,000

ATCC 27351

0

4

8

24

48

The environment of the mouth, as glyceraldehyde is gradually released from the chewing gum into the saliva, is expected to simulate the environment in the TSB test, and thus inhibit S. mutans.

Example 3: Preparation of a Sugar-Free Chewing Gum

A spearmint flavored sugar-free chewing gum can be made with the following ingredients: %

Gum base

Mannitol

Sorbitol

Softener Glycerin

Aspartame

Flavor

Glyceraldehyde

100.0%

The chewing gum can be prepared by softening the gum base at about 65°C (150^βF) and adding it to the mixer with the sorbitol. After 2 minutes of mixing, mannitol is added, after which glyceraldehyde is added, followed by glycerin. These ingredients are mixed a total of 6 minutes, then flavor is added and mixed another 5 minutes. The gum is discharged, rolled thin, and cut into sticks. The chewing gum product will have a pleasant taste and inhibit growth of S. mutans in the mouth.

Example 4: Preparation of a Sugared Chewing Gum

A peppermint flavored gum can be prepared using the following ingredients:

100.0%

The chewing gum can be prepared as described for Example 3. The chewing gum product will have a pleasant taste and inhibit growth of S. mutans in the mouth.

Those skilled in the art will recognize that variations of the above described procedure may be followed. It is to be understood that an equivalent of changes and modifications of the embodiments described above are also contemplated by the present invention. For example, it will be apparent to those skilled in the art, in light of the present disclosure, that equivalents of glyceraldehyde, including various glyceraldehyde derivatives, may be substituted in whole or in part for glyceraldehyde itself, within the spirit of the invention.

Claims

I CLAIM:

1. A chewing gum formulation comprising

(a) a water soluble bulk portion, which comprises from about 5 to about 90% by weight of the gum of bulk sweeteners, and from about 0.01 to about 15% softeners;

(b) from about 5 to about 95% by weight of the gum of a water insoluble chewing gum base portion; and

(c) from about 0.1 to about 15% by weight of the gum of water insoluble flavor ingredients; the water soluble bulk portion comprising sufficient glyceraldehyde to give the chewing gum anti- caries properties.

2. The chewing gum as set forth in Claim 1

- wherein the chewing gum comprises at least about 0.5% glyceraldehyde by weight.

3. The chewing gum as set forth in Claim 1 wherein the chewing gum comprises from about 0.5 to about 40% glyceraldehyde by weight.

4. The chewing gum as set forth in Claim 1 wherein the chewing gum comprises from about 1 to about 35% glyceraldehyde by weight.

5. The chewing gum as set forth in Claim 1 wherein the chewing gum comprises from about 5 to about 30% glyceraldehyde by weight.

6. A method of reducing or preventing dental caries by inhibiting growth of Streptococcus mutans in the presence of fermentable carbohydrates in the mouth, which method comprises contacting the teeth with chewing gum containing glyceraldehyde, wherein the glyceraldehyde is present in quantity sufficient to give the chewing gum anti-caries properties.

7. The method in Claim 6 wherein the chewing gum contains at least about 0.5% glyceraldehyde by weight.

8. The method in Claim 6 wherein the chewing gum contains from about 0.5 to about 40% glyceraldehyde by weight.

9. The method in Claim 6 wherein the chewing gum contains from about 1 to about 35% glyceraldehyde by weight.

10. The method in Claim 6 wherein the chewing gum contains from about 5 to about 30% glyceraldehyde by weight.